Were you entering the New Year hoping to become London’s next mayor, you’d almost certainly want to be Sadiq Khan. An array of polls, pundits and bookmakers are predicting that the Labour candidate will succeed Boris Johnson following the election on 5 May while none are doing the same for the only one of his rivals with a realistic chance of beating him, the Conservative Zac Goldsmith.

While Khan has given the impression of covering every angle with know-how and energy, the Goldsmith campaign has, by comparison, looked lethargic and at times ill-judged. The latest voter survey, by YouGov for LBC, gave the Labour man a ten-point lead over the Tory when respondents were invited to pick between just the two of them, an increase of four points from when the same company last asked the same question towards the end of November. Back in October, the pair were neck and neck by that measure.

The signs, then, are that Khan is on course for victory. But there’s a long way still to go and a wide range of reasons why the outcome of this year’s race for City Hall is hard to foresee with certainty. It already looks very different from those that have gone before and part of its fascination is the constellation of factors that could affect the contest either way.

The most obvious contrast with the first four mayoral battles is the absence of a big personality candidate among the favourites. It will be the first not to feature Ken Livingstone. Boris Johnson is to finally step down from a post he’s been abandoning in installments for many months.

This doesn’t mean that voters’ impressions of the candidates as people will not matter. New Statesman’s Stephen Bush thinks Goldsmith under-equipped for speaking to Londoners’ sense “that the capital is the best place to live on Earth” and says his candidacy lacks the “symbolic potency” of Khan’s – politics-watchers may be tiring of the Labour man’s repeated mentions of his bus-driver dad and council house upbringing, but his personification of London as a city of opportunity seems to be differentiating him from the wealthy, Eton-educated Goldsmith quite fruitfully.

That said, party loyalties still seem likely to count for more than before. This too ought to favour Khan. In marked contrast to the rest of the country, Labour had a good 2015 general election in the capital. The party gained seven seats, lifting its total to 45 out of 73, and took nearly 44% of all votes cast in London compared with the Conservatives’ 35%. The part of the new YouGov poll measuring general party voting intention (see the table on page one) shows that Labour support in London has held steady since then, with the Tories only marginally stronger than they were.

Election analyst Lewis Baston has written: “For Goldsmith to win, one of two things has to happen – either he manages what Johnson did and gets a vote that a ‘generic Tory’ could not win, or Labour’s national popularity collapses.” He tells me he thinks Jeremy Corbyn as Labour leader is likely to continue to play better in London than in the rest of the country. The current figures bear that out. Yet both Goldsmith and Khan are very mindful that Corbyn could still be a liability for the Labour man.

Goldsmith’s team continues to strive to detrimentally link Khan with Corbyn in voters’ minds as part of a broader negative strategy to insinuate that he holds with extreme views. Khan knows that if Corbyn starts to drag Labour down in the capital as he is elsewhere, it could become a drag on him as well. YouGov’s Joe Twyman has underlined that Goldsmith must find a way to get some Labour supporters to defect. The Tory must be hoping that Corbyn may yet provide it.

Another part of the equation that’s attracted much attention is the possible relevance for voters of Khan’s Muslim faith. A poll (again, by YouGov) published in August found that although 55% of Londoners would be “comfortable” having a Muslim mayor a substantial minority of 31% would not.

This theoretical discomfort does not seem to be reflected in the polls conducted since an actual, real life Muslim, Khan himself, has set about introducing himself to Londoners. That’s pretty unsurprising – he could hardly be less like the archetypal scary jihadi and he’s made his views on such people very clear. But the row about the Goldsmith leaflet describing Khan as “radical and divisive” and reports that a Goldsmith campaigner referred disparagingly to Khan as “the Muslim” show that the issue hasn’t gone away.

Khan’s campaign went on the attack over the leaflet. Goldsmith has denied that any coded message was being sent but has been obliged to defend the leaflet in high profileinterviews when he’d probably sooner have talked about something else. Khan’s team won’t hesitate to pounce again on anything else it regards as an attempt by Goldsmith’s team to whistle up anti-Muslim prejudice.

Another new factor in this year’s mayoral battle is London itself. Johnson’s back-to-back defeats of Livingstone were largely attributed to the so-called “doughnut strategy” of concentrating on Outer London where Tory sympathies and a mixed bag of anxieties and grievances have tended to be stronger. This was particularly true in 2008.

But the demographics of much of Outer London have been changing – larger numbers of poorer people and greater ethnic diversity – and voting patterns have shifted accordingly. Redbridge Council was won by Labour for the first time ever in 2014 and the Tory flagship of Barnet nearly fell too. Four of Labour’s seven general election gains were in the suburbs.

The “doughnut” distinction has not completely gone but it is becoming less marked. As well as piling up votes in heartlands like Hackney and Newham, Khan will want to find persuasive things to say to Croydon, Harrow and Enfield. Meanwhile, some highly-gentrified parts of Inner London may hold a bit more promise for Goldsmith.

Other signs of hope for Goldsmith can be detected in the small print of the new YouGov poll. It indicates that around three Londoners in ten who might cast a vote have yet to decide who it would be for. The good news for Khan is that those who’ve come off the fence since the autumn seem to have plumped for him. The consolation for Goldsmith is that so many undecideds still remain and that turn-out for the election is hard to calculate reliably. He can also take hope from the big lead he continues to enjoy among voters over the age of 60. The new poll shows Khan ahead of him among every other age group, but older voters are more likely to make the effort to vote.

Then there is the question of which of the front runners will secure the most second preference votes under the supplementary vote system. It is easy to overstate the likely influence of these on the final result: Livingstone got more of them added to his total than Johnson in 2012, but not enough to overhaul the lead the Tory had established in the first preference round. That said, second preferences for the two front runners could be decisive if their first preference totals are very close.

The first thing to say about all that is that, at this stage, all other candidates remain far behind the Big Two. Some will pick up ground as media attention increases. But, as things stand, when offered a straightforward, single choice from the entire declared field, YouGov’s sample, excluding those certain not to vote, responded as follows:

Sadiq Khan 31% (up 5% from November).

Zac Goldsmith (Conservative) 24% (no change).

Peter Whittle (Ukip) 4% (no change).

Sian Berry (Green) 3% (no change).

Caroline Pidgeon (Lib Dem) 2% (down 1%).

George Galloway (Respect) 2%.

David Furness (British National Party) 1%.

Paul Golding (Britain First) 0%.

(See table on page two. Galloway, Furness and Golding weren’t included in the November poll).

The second preference question is interesting in its own right but also pertains to Londoners’ attitudes on policy themes that Khan and Goldsmith will want to make their own. These could play out in various ways. It is logical to expect that the Ukip voters Peter Whittle is chasing will bestow any second preferences they cast exclusively on the long-standing Eurosceptic Goldsmith, and not warm at all to Khan, the son of Pakistani immigrants who has adopted a strongly pro-EU stance. Though that expectation makes an assumption about what draws a minority of Londoners to Ukip in the first place.

Did some of the party’s votes at the general election in the capital – comprising a substantial 10% share – come from working-class erstwhile Labour voters who felt the party had lost interest in them and their kind, as was the case in other parts of Britain? If so, might Khan, with his humble origins, actually attract some of them back into the fold, especially if he makes the right pitch to the parts of Outer London where the Ukip pull is greatest? That might seem fanciful at best, but please allow me to reveal that it’s a theory others are giving houseroom to.

There’s been a lot of speculation about the Green vote. The party was delighted to finish third in 2012 and will hope to repeat that and maintain if not increase its two-member presence on the London Assembly. The party’s organisation is maturing and Sian Berry, who is running for both mayor and assembly, is now an experienced and poised politician. She believes that the selection of Corbyn as Labour leader has enlarged the political space that Greens can occupy.

You can see her point. Even so, the Greens might be in danger of getting squeezed by both the leading candidates. Goldsmith is, of course, well-known as an environmentalist. For his part, Khan won’t want to be out-greened by the Tory especially on transport pollution and although his stance on the London economy has a New Labour flavour, he’ll sound more left wing on housing as he already does on fares. Plus he’s popular with the young, who form the heart of Green support.

For the Liberal Democrats, the mayoral contest has to be about recovery. Caroline Pidgeon, their very capable London Assembly member who is also chasing the big prize this time, will try to make her mark by highlighting a cluster of specific issues and aim to re-establish the Lib Dems as City Hall’s third place party. George Galloway will seek a hearing as the outer left alternative to Khan.

Can Goldsmith pull back the deficit he seems to face? Expect him – and the media – to put Khan under heavy pressure to explain how public transport fares can be frozen for four years without damaging Transport for London’s investment plans. The traditional Tory economic competence card might come in handy there. He’ll be pushing hard on housing too, wooing despairing would-be first time buyers in particular. His claim that, as a Tory, he’s best equipped to get a good deal from a Tory national government seems certain to continue to be aired.

Two Telegraph writers have taken different views on his prospects. Asa Bennett has listed seven reasons for optimism (some of them explored above) while his colleague James Kirkup is prepared to put £50 – though not his house – on a Khan win. His argument includes doubts about Goldsmith’s ability to match Johnson’s crossover appeal – doubts he says are privately shared by some senior Tories – and goes so far as to suggest that the outgoing mayor, George Osborne “and anyone else who wants to be Conservative prime minister in 2020” might “quietly toast” a Khan victory because it would improve the chances of Corbyn leading Labour into that year’s general election.

Well, I never. The 2016 battle for London may not have the stars of yesteryear, but will be enthralling in all sorts of other ways.

News that London Underground staff plan to stage three 24-hour strikes over the introduction of the late-running Night Tube service has seen the mayoral race front runners clocking on.

Conservative Zac Goldsmith has again depicted Labour’s Sadiq Khan as a screaming red lackey of what he pointedly calls “Jeremy Corbyn’s Labour Party” and a creature of trade unions, some of which backed Khan to become his party’s candidate. Khan has compared the number of Tube strikes under the Tory mayoralty of Boris Johnson with the total under his predecessor Ken Livingstone: 35 plays 16, according to Khan’s maths. “Every Londoner who wants fewer days lost to strikes needs a Labour mayor,” he says.

Is Khan right? What do his figures prove? What useful role can any London mayor play in soothing industrial relations on the Underground?

The comparison Khan makes is imperfect because the contexts for strike action have changed. It helped Livingstone that his time at City Hall was marked by substantial fresh investment in the capital’s transport network, notwithstanding his losing battles with Gordon Brown over ill-fated public-private partnership financing schemes. Johnson, who saw them off, has had responsibility for Underground upgrades during a period in which his fellow Tories upstream have kept on writing cheques but tightened the purse strings. There have been squeezes and cuts. The unions, unsurprisingly, have resisted.

Even so, Johnson’s performance has been unimpressive: sometimes provocative, sometimes indifferent, sometimes weird. His 2008 election pledge to negotiate a no-strike deal was a real oddity. His aversion to sitting round any sort of table with elected leaders of a key transport system’s workforce to discuss anything at all has not waned. He initially reappointed two Tube union officials Livingstone had put on the Transport for London board – Tony West from ASLEF, and Patrick O’Keefe from UNITE – but former TUC general secretary Sir Brendan Barber is its only human link with organised labour now.

Tories and trade unions are not natural allies and Johnson’s accusations of playing politics won’t all have been wrong. Yet his one visible input into Underground disputes has been to seek political advantage from them. That preference too endures: with Goldsmith trailing in opinion polls, Johnson has denounced Khan as a “tool of ASLEF” whose response to the latest strike plan shows him to be “all over the place.” But Khan, by sharp contrast, might see it as his place to make a useful contribution to improving the staff-management mood.

This shouldn’t mean taking a personal role in complex negotiations: neither the unions nor London Underground’s managers would want or be likely to benefit from that. Rather, it would mean encouraging creative compromise and fostering a more constructive atmosphere in which the demanding problems of Tube expansion and financial realities can be addressed. That won’t be easy, but having good union connections could assist a Mayor Khan. They didn’t do Livingstone any harm. He had his rows with the unions – famously so with the late Bob Crow of the RMT – but his political background meant he understood what preoccupied them and how they worked.

The prospect of a Mayor Goldsmith is less encouraging. You don’t have to agree with the Khan campaign’s impolite claim that Goldsmith is a “serial underachiever” divorced from real life to know that his experience of union culture and how to grapple with it is limited. Asked on BBC Radio London during the Tories’ candidate selection contest if and how a mayor should intervene, he argued for more involvement in principle and, in keeping with his interest in direct democracy, suggested that negotiations be relayed to the public live. It’s a novel notion, but would it help produce better results?

A lot of nonsense has been talked about the Underground, its tensions and its challenges. Labour politicians up in arms about Johnson’s ticket office closure programme ignored the fact that Livingstone had drawn up a more drastic one. Tories highlight economic damage done by Tube stoppages but howl against measures to reduce road congestion, which costs London businesses mountains more. Delusions about “driverless trains” recur.

The government has plans to restrict the power to strike but their value to London is questionable. November’s Docklands Light Railway stoppage anticipated their limitations as a curbing device and the whole “crack down” approach ignores the positive connection between union representation and staff morale. The London Underground workforce is a credit to the city. Its unions can be stroppy, but its bosses can be too. Both are integral to the Tube’s future and, in the end, must co-operate to make that future bright. Sadiq Khan is the candidate best equipped to help bring that about.